Honestly, there isn't much to learn. It's just a function that takes props and returns a React component (usually via JSX). The only big decision is the props API.
The best thing to do is just to brush up on functional concepts, thinking about things in terms of composition and application, and threading state through your application and flowing back through to the top via dispatches. Learn more about flow (the concept, not the framework). I like to picture a waterfall, where the water is state that always keeps flowing no matter what it hits. State should start at the top from some source, we don't care what that is, and then flow through the application down into the leaves. Functions can do transforms and reductions on state, but they should never hold on to state the way class components do.
